This applies to any kind of game programming, not just TI BASIC. When I was a BASIC programmer, at many times I had no idea what to make. I will introduce to you what a game is. A game serves multiple purposes. Some are for entertainment, others are to relieve stress, and yet others are to tell a story. I personally prefer the last one. And to make a story, use your imagination. People generally don't like if you copy one they already know.
For Entertainment:
These are the most common. They are quick to make, and are used in popular games (such as Call of Duty, Halo 4, etc.) Make sure there is a reason the people would like to play your game (graphics, gameplay, etc.). Try to make something people didn't already make. That is, unless their one is terrible by most people's judgement, or is a classic (like Tetris, Mario, etc.).
Some people copy games from popular games outside the calculator community. That includes Minecraft, Doodle Jump, and others, and I have seen many of them. These are generally not as popular as some games, like Desolate, which was designed to be a game. However, it is useful to copy some good features in a game, like Desolate may have taken text logs from Dead Space. Don't feel bad about using overused features, like sidescrolling, stats in RPGs, etc.
For Relieving Stress:
This is a common way to make a game. Usually these are amusing, and have good controls. For TI-83/84 games, the controls involve the top few keys (2nd, ALPHA, arrow keys) and ENTER. For example, don't make character(s) dull or flat (Unless it's Paper Mario hahaha). Finding good controls is generally based upon your personal opinion. For example, the arrangements of the joysticks on an XBox controller and a PlayStation controller are different, but different people find different ones more comfortable. If you're really into it, you can make custom control schemes.
For Telling a Story:
This is my personal favorite. Video games, like music or art, I feel should tell a story. It can vary the greatest out of any type of game. Stories, unlike games for entertainment, involve a deeper thinking of the programmer (I am assuming you program as a one-man-army). If you really aren't sure how to make a story, ask your English teacher (it is just like a book!). Character development is the most important part. Character appearances should match their personalities. For example, a person who is ashamed of how they look might wear a hood or sunglasses. Character uses in a game vary as such:
- Main characters: You can often control them, or they greatly develop the storyline. I count the villain as a main character. Make sure the villain is not pure evil. No one likes that.
- Characters to talk to: They can give you important information about characters, gameplay, items, etc. They can give you items and the likes.
- Gameplay characters: Generic soldiers to give a death count, villain minions, etc. In a horror game (not sure how to make a non-psychological horror on calc), you may include a character who dies, just to show the enemies potential.
Features that should be included in all games:
Good controls. It makes the player more satisfied to play your game. Some games with a lot of controls need to spend some time on this. Preferably mention the controls in-game, unless it's like Tetris, which should be obvious. Some horror games make intentionally bad controls or movement speed, to give a sense of being doomed. Make sure not to overdo this.
Gameplay. Make sure the player won't quit out of annoyance from, for example, overpowered enemies. Of course, make sure it is possible for the common folk (don't include passwords not mentioned ingame, unless it's an easter egg :)
Graphics. The player wants to know what they're doing. Give them what they want. Greyscale is just to make it look better if the program runs fast enough. Don't try this with TI-83/84 BASIC for more than 10 pixels.
Re-playability. RPGs are usually long enough to be not repetitive. Puzzle games must be wary.
Originality. What makes your game different from another posted an year ago?
Sidenote: I wrote this because I had a sudden thought, and didn't want it to go away. Hope this helps!
Fire Emblem for TI 83/4+ Progress: Demo: 75% Total: 40% Postponed indefinitely