I had to create a combat system for The Cursèd Pickle of Shireton and while it was very simplified, what I came up with was a timed-clickybox system.
Timed events are often the bane of players’ existence, but this seemed like the best way to go. Essentially the player was told they were being attacked, and then got a screen listing all their skills with buttons. They had a certain amount of time to both defend, attack, and prepare spells before the creature then attacked them.
If you wanted to defend, you would hit that button, then you got a couple of extra buttons to click to “reinforce” the attack. Fighter types got extra and that basically determined how many points of damage the player would deflect. This took time to click all the buttons of course, so that was the tradeoff of defense vs offense.
There was an automatic “Wallop” button which was a free attack doing one damage that always hit as long as the player’s level wasn’t too low compared to the aggressor’s. Depending on the player’s class and weapons, they could similarly power-up their weapons by clicking extra buttons to make them more powerful, again, costing time. Casting a spell required clicking on a grid of magic syllables to create a magic word. The bard had to click on the right strings to play on the lute to cast basically a spell.
The player could also hire NPCs which basically increased the number of attack and damage buttons they had access too, again requiring more time management to figure out which attacks worked best in any situation. If you were against a weak enemy, it might be better to concentrate on bigger attacks to finish them off quickly and not worry about them dinking you with one HP each round. The NPC basically also offered a layer of shield - if you hit 0 HP during a fight, it killed off the NPC first instead of you and you got an extra bit of health to hold out or flee the combat.
My strategy playing was always DEFEND TO THE MAX FIRST then click everything else you possibly can.
When the time ran out, all this built up damage was thrown at the aggressor who might deflect some of it.
I put in an easily-findable cheat knowing that some users aren’t good at fast-clicky mouse action that slowed combat way down for them, and there was a way to run from any combat as there were only a few required fights in the game. In most cases, battle was grinding for loot.
If I’d had more time, I would have played more with the attack timing being adjusted more based on the player’s level and spells in effect. As it was, you had normal combat or really slow combat if you used the cheat code the game provided.