Hi folks, I'm the author of MartyPC, an original IBM PC/XT/Jr/Tandy 1000 emulator, and I'd like to humbly suggest it might be useful for people making retro games for the PC, especially targeting the original 4.77MHz 8088, as it is cycle-accurate.
I would like to think its a pretty gosh darn good substitute for having a real IBM PC lying around to test on.
It has an easy to use debugger with breakpoints, disassembly, memory inspection (including graphical visualization of memory). You can view the state of the video card and all the hardware peripherals in realtime. You can even watch the raster beam draw across the CRT as you step through your program!
You can try it online in your browser: https://martypc.net
Or try one of the binary releases for Windows or build it yourself for Linux or MacOs: https://github.com/dbalsom/martypc
It's not quite as convenient as using DosBox perhaps, but you don't necessarily have to struggle with making floppy disk images - if your game will fit on a floppy you can just put it in a ZIP file, and MartyPC can mount your ZIP as a floppy disk.