Any laptop stronger than this one right here can run Risk of Rain 2.
To run Risk of Rain 1, you probably won't need as much horsepower.
Either way, head to Facebook marketplace and look for gaming laptops. Then, look for;
Windows 10.
GB of RAM. You want at least 6gb, ideally 8-16gb.
The GPU or Graphics Processing Unit is a little more complex. Find it in the post or ask for it, then google "[GPU they tell you] vs [the GPU from the Amazon listing.]" If it scores higher than the Amazon listing, you're good.
The CPU or just the "Processor" must be handled the same way as the GPU. "[CPU they tell you] vs [the CPU from the Amazon listing.]" If it scores higher than the Amazon listing, you're good.
GB HDD or SSD [Hard Disk Drive or Solid State Drive. HDD don't settle for under 500gb, SSD you want 250GB+. You only need a small portion of this for RoR1+2, but its nice to have space for other games.]
Congratulations, you've spent between $300-$600 on a machine that can run games like RoR2 at low to medium graphics. While it's not always the best bang for your buck, it's the easiest for newbies to the PC world to dip their toes in. Your next goal is to save up $3000 so you can build a high end PC.