Here’s a little on how some in-game controls and overlays work.
After we had the tiled map up and running, we thought about how the controls would work. Most of the TD games we’ve played had a pointer since it’s either on the PC or Xbox 360, so how would this work with a touch screen? Hmmm.
Following the same train of thought about dealing with player experience, we realized the necessity of a HUD (Heads-Up Display) as well. The player need to know how much health and coins they have, what wave of enemies they’re at, etc. We needed a system to deal with that as well.