Not too bad
Actually kept me playing until I lost (level 9).
Consider adding these into your list of features, if not already:
- On the title screen, change the Textfield, so that the text cannot be selected. Also, try using a font that matche that of the "Play" button, even if you have to remove the Textfield and just draw a custom label yourself. Same with the upgrade screen.
- Better graphics. There are some freeware textures on the Internet you can use for the walls.
- Sound effects.
- A Health power-up, so you can regain health, or add a health powerup "ball". This ball behaves just like the rocks, except that you must let it touch you to regain some health. If you shoot it, you either destroy it, or it turns into a regular rock.
- Slower moving, larger rock, that either (1) takes 2 or 3 hits to destroy; or (2) takes one hit to destroy, but breaks up into 2 smaller rocks.
- At the end of each level, don't just suddenly it. Allow all the currently active rocks to complete, then end the level. I imaging you're either doing each level based of a set amount of time or a certain number of rocks. Either way, once that limit has been reached, don't produce anymore rocks, and wait for all currently active ones to be removed.
- Some additional power-ups to consider:
1) Money power-up. When you collect it, it gives you a nice chuck of money, OR it adds a temporary multiplier to your current gains from shooting rocks.
2) Temporary invulnerability.
3) Temporary speed debuf on incoming rocks.
That's probably enough to keep you busy. (:
- Ziro out.