Despite how concise & short Scarlet Heroes is compared to other retroclones, I have been using it at almost every one of my gaming sessions for several years now and I have yet to exhaust using it. It has become one of my most heavily used & favourite products from this store.

It has many possible uses & it tends to excel in everything it does.

But above all else, it has become an indispensable tool in most of my solo & GM-less gaming.

This is because:

1) Instead of just faithfully cloning B/X at-length as most retroclones do, Scarlet Heroes tweaks B/X's traditional rule mechanics & other content into something which is still B/X-compatible, but it is much more tight & concise for optimal use in solo & GM-less gaming. Plus it integrates adjustments into that for playing with just a single player-character or two. No further adjustments are needed to play a single player-character with it. (This would also make it a good choice for one-on-one gaming.)

2) It also includes many random tables throughout it, which essentially cover almost everything that I might ever need in any of my solo & GM-less gaming. Among other things, this includes an excellent oracle, as well as many tables for NPC traits & behavior, urban/wilderness/dungeon encounters, adventure seeds, plot twists, & much more.

3) It also comes with its own self-contained setting, bestiary, & spells. Plus it is a wonderfully exotic setting to play in... Even just some of its fantastically Junji Ito-esque monsters alone would make it worth recommending here.

In other words, Scarlet Heroes has everything that I need for OSR-styled solo gaming in a single book.

My only caveat here is that if you are looking for a standard B/X setting with classic B/X monsters & spells in it, you won't find much of that in Scarlet Heroes. You would have to find that stuff elsewhere if you want to include it. Then use it alongside Scarlet Heroes while you are playing.

That being said, Scarlet Heroes works extremely well in-combination with other B/X-compatible games & supplements.

E.g. I often use it to augment some other B/X-compatible solo-gaming products, such as Ruins of the Undercity & Mad Monks of Kwantoom.

Plus I use its random tables a lot with some non-compatible games, such as Four Against Darkness & Ironsworn.

The bottom line: Scarlet Heroes is my main go-to resource for most of my solo gaming now. No matter what game I am playing, I seldom play without it.