The software house Retro Software has been around a few years now but - until this year - its professional releases had been limited to BBC Micro games. Hard Hat Harry is the first release it has churned out for the Electron. Better still, it's Public Domain and won't cost you a penny to download. Written by Tom Walker, who is the brains behind the B-Em and Elkulator PC emulators, you could be forgiven for expecting greatness.

Hard Hat Harry loads up with a Micro Power style loading screen; the tongue-in-cheek instructions inform you that you need to collect the mugs from 20 storeys of a highrise tower building to appease your hard-hatted workmen colleagues. Doing so will net you a good reference and a "job as a banker, or something". This translates into a ladders and levels game which one cannot help but compare to the famous Chuckie Egg. You can run left and right - and jump! - and climb up and down ladders.

So far, so good. There are a variety of obstacles that conspire to make each screen progressively more difficult to complete. These include gaps in the platforms, conveyor belts (on which you will do a 'superwalk' rather like riding on a conveyor in an airport) and deceptively placed overhead platforms on which you'll unexpectedly bang your head.

In addition there are animals loose in the building. Monkeys lob spanners at you, the Gorilla throws barrels at you, birds fly back and forth and need to be avoided - and the Panda just gets in your way. All can be avoided by dexterious fingerwork and the art of completing a screen seems to be an exercise in remembering the route around it, and also when to pause.

This is because every adversary bar the birds is completely stationary, and seems to operate to a timer. Better still, before they attack - be that throwing a spanner or a barrel, the Electron sounds a hollow thud. Your brain can just about register where each animal is on the screen, and also whether or not you are in its current line-of-sight, before it unleashes its weapon. Then, depending on where you are, you have to scurry out of its way.

The toughest adversary seems to be the Gorilla. His barrels come flying at you twice as fast as the spanners. To avoid them you usually need to stand completely still just before a barrel is thrown, then quickly run out of the way. Even then you can be unlucky.

Earlier I compared Hard Hat Harry with Chuckie Egg - that might be enough for those who love the Chuck to have already browsed over to Retro Software to download it. It is similar in layout - and the touches like being able to fall as far as you want without dying. However, it does fail to live up to the high standards set by that platform game. Firstly, there are some irks with the control of Harry - the collision detection is almost too perfect. There's no margin for error; one pixel out of place and you're a gonner. Also, you often have to jump from the very end of one platform. I encountered many times when I instructed Harry to jump and he ran straight off the edge!

Secondly, the game is rendered in Mode 5 and the colours chosen are odd. The background is a garish cyan which flying spanners in yellow cannot hope to stand out against. If they were blue (which is used for the ladders), then you'd see them coming. Goodness knows why the programmer chose to use yellow.

Thirdly, the jumping itself seems to vary by how long you hold down the RETURN key. If you hold it down longer, Harry jumps further. This revelation sort of dawns on you when you clear a gap on some tries and not on others.

Fourthly, the instructions are inconsistent with the game itself. The Gorilla, for example, has picked up a screaming maiden from somewhere. Yes, she might be a nicely-rendered sprite, but Who she is, is not referenced in the instructions. It's confusing; it's like you're suddenly playing a variant of Killer Gorilla for one level only.

And whilst we are on the matter of instructions, I cannot for love nor money find the 'elusive Stripey Paint' object they mention. (This is meant to make Harry invincible for a short period of time.)

But most disappointingly, the game describes 20 storeys of a highrise tower to be cleared of mugs. But when you get to screen 17, you find it is exactly the same as screen 1; and when you clear screen 20, you get a screen 21. Hence it just seems as if the game continues ad infinitum! Considering the effort you need to put in to reach any level after level 6, this seems little reward. Even a quick rewrite of the instructions to say "16 storeys of fun" and a congratulations screen after level 16 would be better than a 'wraparound'.

It's all a bit exasperating, to be honest. Hard Hat Harry is a good game - the graphics are not 'terrible' as Tom Walker suggests in his writeup; in fact, the graphics are a darn site better than the graphics in many commercial games of this type. The playability factor is high and there is a great deal of strategy (and indeed fun) involved in working out how to traverse each level.

But if you read Tom Walker's development diary of writing and releasing the game, over at Retro Software, you see exactly what has happened. The author came up with a 'limited' (his words, not mine) design, worked to a deadline and, because of memory constraints, ripped out some elements of the game in its final days. But unfortunately, he did not amend his design document as he went along.

Hence we've got instructions that still speak of 20 storeys (when there are only sixteen), instructions that speak of a finite set of screens (when they are now infinite) and instructions that speak of stripey paint when this element doesn't exist any longer! Maybe he also toyed with giving Harry a girl to rescue, but that idea wasn't put in the design document either, so her appearance just seems bizarre. And finally, because he worked to an inflexible deadline, he decided it would be released come what may on 23rd January 2011.

Now ultimately this means us Elk lovers have been blessed with our first 'real' game this year - and it's a good one, so the above huffing and puffing should not detract from a platformer which requires considerable skill to master. Take away Tom Walker's instructions, and you have a game which is playable, if a little confusing in parts - but which you will enjoy completing. I just find it tragic that Tom Walker did not stick to his original design. It's clear he never intended originally for the game to go on forever. That it does means that the player feels cheated by the omissions and when he hits screen 21. Hence meaning the rush to release it means Hard Hat Harry pays a price of being recommended only with this proviso.

Hard Hat Harry is also reviewed in Episode 27 of our FIVE GAMES FIVE MINUTES series of videos.