It's cute and fun to play like TANS's original. It seems a bit more difficult to play than the original. When I posted a test version in the #gamedev chatroom, people were getting up to levels 10 and 15 without much trouble, so I added a bit of code to make the blocks get more dense as the game goes on. Around level 20 the level should be half the width of the screen and 20% of usable screen should be full of blocks, so it should be durn-near impossible by then.
Game Design Hint: If you're making a game that doesn't have a clear completion point (like "Zelda") but just goes on forever (like "Pac Man"), figure out a point where the game should be impossible to play rather than having the difficulty "level off" somewhere.
Also take into account people not playing the game the way that you'd play it. This was a problem that Zap Pod had originally. The object of the game is to shoot ten rocks to move on to the next level while avoiding the other stuff attacking you. Problem is, the level itself doesn't get more difficult as time goes on (i.e. level 2 is more difficult than level 1, but level 1 keeps its difficulty). That means that if you avoid the rocks rather than try to shoot them, you'll stay on level one forever without the game getting more difficult. Version 1.1 of the game makes the individual levels get harder over time, so you've eventually gotta shoot all the rocks and progress, or else you're doomed.
One of the most interesting things about JetLag (and I've always been fascinated by how addicting it is-rivals the addictiveness of tetris-and have always tried to isolate the quality that makes it so-with aspirations of making other games equally as addicting) is the zig zag movement, and how different the game is if normal straight-down movement is allowed. It is not the same game at all. When a player is playing JetLag, that is ALL of what he is doing. You can't do it while chatting on the phone. You can't smoke a cigarette. You can't eat. You can't drink. Your entire attention is fixed on that stupid little smiley face (or in the case of john's game, the little worm head), or if you are a more skilled player, you are fixated at about half to two-thirds of the way down the screen, and using peripheral vision to steer.
(side note: one of these days, I should go back and redo the version that existed for the TRS-80 Color Computer 2-originally hand assembled 6809E code- for use in an emulator. you would all be very surprised and disappointed by what it originally looked like.)
Oh, and for those who follow the exploits of John and may or may not follow the exploits of Me, it is an entirely normal thing for us to rip off each others games or sections of game code(for example, I use John's random number generator). It is normal and even to a degree encouraged, as we feed off of each other's ideas and both of our respective games wind up the better for it.