Great short game for your old PS1
Fear Effect has an interesting plot and you will be switching between three characters, which keeps the game fresh. You have to solve puzzles (I had to use a lot of help with those) and have the option of different weapons to choose. You can use two of them at the time that when aimed to two coming towards you will save you some damage.
The game can get tricky at some points, like the puzzles, and at the end you have a choice to make, not going to spoil the ending but it's a good idea, you can see both ends just by playing the ending again since you'll have the last save checkpoint. It's a fun short game for your old PS1.