it's simple to build a simple one... but the more polished takes more time. Why not just offload that work to someone else? That's our view anyway. We've chatted to some potential clients and other companies running their operations this way.
So the difficulty ramps up like this: it goes from 1 to 100 every 60 seconds, spawning more difficult enemies as it increases. The difficulty increases faster the more damage you've taken. Once it reaches 100, it spawns dragons, resets to 0 and doubles the amount of monsters it will spawn.
You can reset the difficulty manually by working your way up the weapon tree to the RUNEFORGE (purple sword)!
Glad it was still fun despite your frustration :-)
1. Wait for user input before loading
2. Load up a "sound sprite" (kind of like a sprite sheet for audio) since iOS only supports playing one sound at a time
3. PROFIetc.
That says there might be a need for it, but on the downside it's really simple to build, so competition can spring up very quickly.