I came across several problems with your game:
- I tried playing the game is Safari and Google Chrome, but whenever I do this, my character won't move; the game will load, but the awds keys and space bar do not move the character. Luckily, I had Firefox, which it did work on.
- The screen seems to be partially cut off at the top and bottom. At the top, I can only see 3/4 of the score so it's enough for me to tell what it is.
- Some of the prices for the items to buy before playing the game don't appear under them. I think this occurs on the second attempt, as I don't recall seeing this problem when I first tried to play the game.
- Your description doesn't seem to describe enough of the in-game mechanics to its fullest. What I mean by this is that there are some unanswered questions that are hard to tell due to the graphics of the game that should probably be addressed. How long do in-game power-ups last? Are the upgrades you buy outside the game permanent? How do you get a multiplier in-game (I know you describe it in Help, but I tried waiting until the last second to shoot them, only to end up being damaged and not gaining a multiplier. Maybe show an example in the tutorial).
- the Flappy version is an interesting take, but there is something seriously wrong with it. It worked fine for the first few times, but after a while, it seemed like an invisible wall was keeping me from moving through the openings. I would jump, let go of the jump button and hold the right directional keys and it wouldn't let me through. Plus, you literally plunge the player right into it without any warning or notification; there should probably be a count down or an instant reset instead of a hold down reset. Lastly, the control setup is weird since you not only need to use the mouse to kill enemies, but need to keep a finger over the spacebar, right, and left directional keys to be ready to move. This is a really awkward setup (especially when you could have made it be the w-key as the jump to make it simpler). And keep in mind, this is coming from someone who has an american keyboard, people in other countries that have the keys in different places are going to find it next to impossible to play your game because the aswd keys are probably not grouped together (or at least, that's how I've come to see it) so you may want to think of adding the arrow keys as an alternate control setup or put in a option to let the player change the controls.
Still, I like the graphics or the game and could definitely see this going in many different directions, depending on your preference (It actually reminds me of the effects in KOLM). As it stands, it is good for a first game, though it needs a lot more work. I wish you good luck in your future of game creating.