  The class of Guaranteed Scoring Games (GS) are two-player combinatorial games
with the property that Normal-play games (Conway et. al.) are ordered embedded
into GS. They include, as subclasses, the scoring games considered by Milnor
(1953), Ettinger (1996) and Johnson (2014). We present the structure of GS and
the techniques needed to analyze a sum of guaranteed games. Firstly, GS form a
partially ordered monoid, via defined Right- and Left-stops over the reals, and
with disjunctive sum as the operation. In fact, the structure is a quotient
monoid with partially ordered congruence classes. We show that there are four
reductions that when applied, in any order, give a unique representative for
each congruence class. The monoid is not a group, but in this paper we prove
that if a game has an inverse it is obtained by `switching the players'. The
order relation between two games is defined by comparing their stops in
\textit{any} disjunctive sum. Here, we demonstrate how to compare the games via
a finite algorithm instead, extending ideas of Ettinger, and also Siegel
(2013).
