Vice City: Rampage!
The Rampage or Kill Frenzy has been a feature of GTA from the very beginning. The basic idea is that you’re temporarily given a weapon with unlimited ammo, and you have two minutes to kill a certain number of enemy gang members (or occasionally innocent bystanders or even cars), which will spawn in greater-than-normal numbers around you while the rampage is in progress. If you succeed, you get a cash reward that increases as you pass more rampages. This could obviously seed a feedback loop that encourages people to keep seeking out new rampages until they’re exhausted, but I personally never got that far into it, even though they’re necessary for 100% completion. Rampages carry the risk of harm, and can sometimes attract police attention. But they are a good opportunity to try out weapons that might not otherwise see much use. In particular, it’s often possible to find a rampage for a weapon before it becomes available in the main game.
The one thing that’s changed from the original GTA kill frenzies is the way that they’re triggered. Originally, the trigger was picking up certain specific weapons lying out in the open. The kill frenzy weapons didn’t look any different from ordinary weapons, so you’d sometimes find yourself in Kill Frenzy mode unexpectedly. Vice City instead uses special rampage icons that float in the air, slowly rotating. I call this an improvement, but it does mean that when you attempt a rampage for the first time, you don’t know in advance whether you’re going to be rampaging with a rocket launcher or a katana. This is a significant piece of information to withhold from the player — particularly if, like me, you’re doing it primarily for combat practice.
Speaking of which, I think I did in fact gain from my practice, and I intend to switch back to missions in my next session. But I think the main thing I got out of doing multiple rampages was an appreciation of how much easier combat is using mouse/keyboard controls. I had long since given up on using a controller for first-person sniping, but now I’m giving up on it in general. Even driving seems more comfortable with mouse/keyboard controls at this point. Strange, considering how relieved I was to get joystick controls working in GTA3. There may be some grass-is-always-greener in effect here, with any control scheme I’ve recently switched to feeling better simply because it’s different and alleviates the inconveniences I’m aware of at that moment (while introducing others I’m not paying attention to yet). But even taking that into account, mouse just seems like the way to go in any situation where you’re aiming a gun.